SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2ca21e22795b5180f997c231ed74fa2a5a021e3c2d5ccc7a278ee9e19322cfe3' 
  AND token = 'E6Pw//YS2bcXzW8zXzZ+MnyHU27BCZWDsCcQKntFXbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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