SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f16a6d5b39ac615523189f5a21a6f7c32f2937aa325aff8867a05a473321ddb' 
  AND token = 'vZBABNCNUOkgD3NnIiz9MolLRsAKjb3rwgjSRN9FinM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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