SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b31a92dde80e13e7544ebaf28db0d5b44371e68cf64e8f05b3515fdf7c52f33c' 
  AND token = '4zVTqxv2HUuGBnNFqS7UfrAbxxUhGcvPg0oOY0dOOAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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