SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8af7a069722a01e9a105a04afee02206eb272b2ccfa784c0162ce6d5fc2188ff' 
  AND token = 'NvEOMZDQElx9UKGJFDxSGJGKyrPKfNMzZ8HJRW11/Vg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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