SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8b47cb7ef74fd3612b192dc0840e3f17aa844945538af502fdb88cd141c7c09' 
  AND token = 'VhnwaXIAZmJ4UUEYSR4urRmzH24ZC6vL+ugK7IuqcBA=' 
  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"
    }
  }
}