SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4133750feca4dc729c189a2ddcaa774ff856418b329ae385eb65a029cb026e9' 
  AND token = '8nMGn9qDuTNEnT7jNpi0fjElvxZzYvE/kGAK9VGmqow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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