SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f311a872e08c26530a0ead661aac042b73646d9488ee190a3478252b63cea63f' 
  AND token = 'Etv0eacJ4KcwfmDWXlBzHlCy/iiQkQTaFTpZAWHO3EI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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