SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c143581136813f142399569178219fa4ed2f20cbf6eb31ade08b6de8d7140f2' 
  AND token = 'TdZS3mv0hmsqhXdZPjhW37fHcBpv28np0kBCrb2Y1GU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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