SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '138d56169fa170f8cbd43e772478f0b9459fb4621986535007b18c693036e29c' 
  AND token = 'IMgZBCwPdGsuqWv0a1JDxxl8J3iMUOfzIIFfrqHoqiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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