SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9736a5d1527ae0cf0bf4ce2b9e10be48b18b116524aea1d68cd385735a5b47e' 
  AND token = 'cQlbvwgW+zms0QfHGgoGpjMZDqME7WveXnucqOuktFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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