SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44a47fe3582b492046561baca675ba663f9c20b217cb8fa1c356df2e1d694aef' 
  AND token = '6ci3wswVcnWhaQBK7tXYqfPFozeDEQpX+Jmfb7fDNFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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