SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2254a0c385a687e590aee037a8b48049185560e94d2abcae4bbf79c5569a4a1' 
  AND token = 'jhIGy8zO/2xnSmAbLq55BANAMUzIHS7jZMyZ7/zL6bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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