SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '919211f62a1dcd6a3650103209bcfcfe29a7642f51637c27f3b8881560964857' 
  AND token = 'Ur28bZ4ECz7TqSk6LXy2r6K4MVIwyuataQDZ/BDmQh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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