SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a93f58b2b39eb341780309cccc8f8659ae24445d06be30e3e42b195f6b9ca687' 
  AND token = 'Par9UDUKIyfb9AqDnxJ6yBoF6hXVwIZPVGgpDGTIzcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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