SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '102c0d268c9394ded2b2246c112afee58f9a0232b3c647aaf9471921c3f891e5' 
  AND token = 'ouyXBE82soUTmAWclAL5hdXkKjmm0/W5REYD3c+JmYc=' 
  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"
    }
  }
}