SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56965fc2337087e024c233eb258db994fb850f1b755de9d1272e7a7554308c6f' 
  AND token = 'aSzfPSirGP8nWzdKZN8caOnzxdVMuGsZWnA1bVMD7uU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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