SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd6982a90293aafea637c6efb73ec7eb04ac5540432c414c618395a995480b18' 
  AND token = 'U49p9hqnGlFf2qhd9Dcjdz1cCYXlCwv7ZQ7zt++LdIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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