SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9206885476557cda5261f52594388c8482fe9ebb2d87659916d377aace418b6' 
  AND token = 'dNtvDfYCWRuDJh7lbawGBkw3VswyM3FU/tOlm88/Eu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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