SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f93ffdd9ab2d0c81858cb82c44151430850cf769b57fe6b94e3f125af8d01a76' 
  AND token = 'rtTsU3VEiRGK8nho2q8DwkzCwh/xSzq93anyjNN9utk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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