SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10973f44290f103b4247f341febddedc604c5f58171262c87e0457d9009a9985' 
  AND token = 'hhIYwzgwnTr+h4NLzt6wTPHY1qqscn+3ViQ0JQzf6gE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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