SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e19b0481cc1f47abe3fd17b0dcefe654824a3c8e4857ca1f6901b33749419ea' 
  AND token = 'fb1NSvVhnsymBjPDukYcQl4iIqf72kjNlqKOmZynnuQ=' 
  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"
    }
  }
}