SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3b12c7486a6e343b4f2d793d9dd71519056f69b6812fd3803736af8857596b5' 
  AND token = 'BPm4xzZmOfQJpNylBpwG9El3RfRp0M+cSHr3mG3Rd98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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