SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b71b706237d615bda2601eab22bffef8919f6ed17b587f419e03d7131f189ea8' 
  AND token = 'SqrP3lFNE0adx4VIEFgu91L2Q+bsjBIJ0EdraxG4Uw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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