SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34d2fec3fef1df534e1d0a76c5a9b11430506bba74d2ae71d9754be15d268be2' 
  AND token = '9zal8gKmd9LvGkCvW/iB1FT9PHr/xyPcDlBp6sQgG9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}