SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f4d451993a1f1ea4f3313576f62c2b5e440c13acec71e9027344fb84179be0e' 
  AND token = 'KQcE9cheEAOGSuZXTbZLBloSqujlZ8ho4qbLxIgGoCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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