SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd74f1dc6756c411e6dc6ae4ac7a76c2f6ed58e10bbbbb3f5dba21f86d9f8758' 
  AND token = 'kv6RWLy9SIKCHtbJahagEpEFWSZWvCBOqZYasHfcOj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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