SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec8795fa8e84c6143f7a68d7c26ddaf27f60dc5c69fc9164c08b174fd31f43b4' 
  AND token = 'RBc7KMP2C6rssXpjnyJX/mSDSchPKmy5OWILTLL1CV0=' 
  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"
    }
  }
}