SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73308eb475611853f00421f8e4f5a0396016a643e37ad3661f9373803342b79b' 
  AND token = '19Uq6P6V8IX9G4roOE4LbQWIUHeqvWsz0hWN3U40U/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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