SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c004b2c287a17e1b9eb9a75079c2d2e444bd5e8c853b82287b391bd83f8142c' 
  AND token = 'yJaMKT+JhDDXZLfhtgkUbVqBclxYBcln6GgsFyEhUow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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