SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2bce6336f34f09bc53f2f0f977be01e71b12a2f7b032332fc2742f6960d45f4' 
  AND token = 'bdeiIXQQCxFAs4eSsRqr6Ynh9bpE4jISfNr5UPpuKto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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