SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0e7027c8346866e28b95cd664f4929b18e995ee2ca38240d59d350b642e1f8f' 
  AND token = 'BfHEezXgXGww0Vctd4Bug/aDbpscNPdrSc3NWaMihvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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