SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '814853d4a7e1cebe79b1e0d04f1d1b9eeca0a1b3d2ea7b6e179e4df8a870bf78' 
  AND token = '9KgstekgFzTvmq7Rk3hzKZH/PY8DjFUlhp/TqLRno2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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