SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9dc66295e668d00bf29fa061c6c78112d4a767b489592219bb1d2d5d061eb61' 
  AND token = 'csOjYTjQJF92BG17tCwtKnsvy3pxQG+iLVbGj8LXTZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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