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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b40bd15ef6429ecd5fbbbac97dcf8588007ef73b05adedc3db2721545b5709e1' 
  AND token = 'VvZEKnjGgcaX8YlX1PhhYpbFS9OUyct8c5eBNQ9HsbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}