SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5407cf39ddc8d66bcecad31362083259d764609529cdfcea291d0d22d753dd1' 
  AND token = 'n+fSZTlwOh1OQxpUrnOh1rSSXoOvQrUmU12Q4Lh6B9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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