SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'df9d69132319fb4ccf0489ea12644ec5e8d6c501bd2c10a00858be6a0cc39c7f' 
  AND token = 'IWtsRhWvZWKeUtaCwmBP/bS4sJ/0zU6Qbfn6nGOPLEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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