SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0938c54f8cae32c2ed64542501cff459358712468b40557ec472010ef5f7cca' 
  AND token = 'EeQixv1iY9fXzZH34vT3FCpMd8zEPZXyGJtNZJdomO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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