SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98377513b28e2392108ba59f25cf20406eb6c688b5449d9d2b51a54ecc5adb26' 
  AND token = '56lJtgZlDUnDA3SKGXjSuvEhPrr7BQ6t7AExPGseFyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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