SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '40f2399ba13c70e598d529934996f745b6765a849fb72df6614b111560af8263' 
  AND token = 'yH8fJeo9/1v9TaFptAgPgBUpkOt9/zqXRlSftSQ8qvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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