SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d90c08c4eb7e53b8fbfc2887fe1a2d1f224c770b32cd41d4affc6567b41e20a' 
  AND token = 'm/udFF653PRJ0B2CzpU0qUTHDyWgXzF5K5G0lwjsW5w=' 
  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"
    }
  }
}