SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '547cb8d96d77e03cb41c0974dc8130b06d14311a314bb03d18f791c1d3093d9a' 
  AND token = 'mcrwaySVTTLstB5zap7/UnnduQwYw0WmcdvQAPk+8Z8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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