SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74da661476ae8fab2bf907bdcea201cf63093998d3ddb87046c7fc07959651c0' 
  AND token = 'N+7iq6SFx8LAwl+WkD8z2KtSMKdkoqYKJjwG/6K5PQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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