SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c82506c8dbf8c9a646f76b63c4201399625a54ac1146171d6978b220b3b4dc38' 
  AND token = 'YZPfk5WhyQJIbhhtnnjYClnCfeY8qnSFY7JcHNKdxhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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