SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88b6d8082e64dc3104213991c9ec8e4e516f26243181c908cd285d797aa827f9' 
  AND token = 'bV7rfdHumPJuAsVSD03nSKkpDqAr3aQzB8T2jESOcBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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