SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76cf64dd7fd345d3c738158dc82abb92228f3e6b701bac0caefd39b93e7ca28d' 
  AND token = 's+79xe/bBS2wrPRoBBjf8dvjhGXoR1n52BvrY8MlV7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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