SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '352a90df6a05543fd5d877974fc14d7217f700d09329efe899daa4fd61349804' 
  AND token = 's8qpktrGMNNS6RTXoN5EAVZHtH/Gc1tfA6ElLvXWg/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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