SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d11122d52ae4bc879be7b4421f2350414f50b4ac745357bc6970fbbbc0f9a7a' 
  AND token = 'MWJCYo7osP9bgJKh+8h2BLhzHB6FvYjZLqacLhtuzHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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