SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b23626226e161b7f4f578da8208290eef932e361fad18a459f3db98908be3c34' 
  AND token = 'g80CO/c20ScPSRVE1REc3XKQMZY00wWxcqs2csQHmLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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