SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fe793ee89cd5c1faee84806b710314071275a3da8cd40138f96a4683e8eaccd6' 
  AND token = 'F+nPJyvXk1RSkPzaQU6/3ujLfWS4Dx6C5lpEYdxbZWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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