SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5279aab4ae3eb7bef5491c82788fc59faaf0cd6ee030c4d920015b109ca38e9' 
  AND token = 'kkDHmBudlSnNiZymIPflMwDcYmDegDbUZPeUs0vb3+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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