SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '568d6f3ba35bd2b69e24f6e14d2a3867daf2569697073df3df3f5ed5a2699ca6' 
  AND token = 'UuqngNkBrt3BPPRGLJcgFhGvJexZFD75nQKa2KJs6iU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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