SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86c76d2d2f1e5b3bfbfcf1a049f9efb4d76f857d825a9a6f548bd2ad917fe844' 
  AND token = '3wxhYvL5NgDqVS2hQAH+eiIAOotx8jnBXRZi6rhCHQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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