SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d537f9ccd433c85571a37b6af0ca309157ef0329d6761452d9f6e78e996ede3' 
  AND token = '8F+e9/Frb7Zh4TZg1U4VSPGEL/JojbovAgJwtwQ1hdY=' 
  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"
    }
  }
}