SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08e0cd7032243ebcbfd5bd5278f1a8672cb236f2da5a4e410b06391cc69f0c2e' 
  AND token = 'kYxrQHJG7xxKnwuioWBKcoAgC8J3Fvx+CFxzB3kFl/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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