SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb8cc7c20954bf3810a7d8d89d86a30651216d74e85c2288f2bbe190999cdf9b' 
  AND token = 'vf0AdHMzFesGDHGhPF8vXQ2FNZOmjwVH9Jj4Sf9cQxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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