SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbd0816bdc6c0751a24596b6bb6c638bdb18cb95a59c685005a0230521267e2b' 
  AND token = 'WpgAUgzIa8+AiSlKpWvMiUo4rZfqpA7kiqPAeGf1blU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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