SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45c5bc39c61f5983aa3718ceb016ae0985d9f6bdc262758b74ba6f668011b368' 
  AND token = 'BbPGr4MaDmwqYsig7hpzKe1djeutOcpsYDym7dT+LXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}