SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adb1ae3513c3d347081ec3463f4657d988a545c8e27a2595d3f7a2712ee7c8f0' 
  AND token = 'dl1MV/GVSlWEvw70YUgmUgJdd/I/+aFXafg6z+7temQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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