SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c2ffb5dc470248a2bb88895e5fb27a9b419e3619d9c9427324fe25771957133' 
  AND token = 'uYOaLGcjfQj0wruganD1yV1mvG3mKWek1A/LLkOe7WQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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