SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '803b53c84527734814986463e9f2444b05d65176beddd452129ebacb3d5d4c80' 
  AND token = 'ZHoaCxhr84KP5KvVJiZB8B35EHjRr3vNrf7H8iY14gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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