SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4348446cb5a3050a6f5eb6dcf8526eafff1ba70976a83628f9dff1866cddd05d' 
  AND token = 'rsTKouxRkj9Rj99yF2Gch+Lea141NI3ZKTlssOMUi6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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