SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f78c98e53288a18f906811951e00a461b3b26c7577f7d105fec80464d552b530' 
  AND token = 'qpoyVj9fLfaafdfKw+RPcVvhYgZNLvK4gfeK0xBowt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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