SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b991dbaaa3d66c50cc28b79e28c5a93ae5fb8ef930c55c355e41ea9a7f2d3419' 
  AND token = '1ps1WGcLhnpLKBGhuxEr/LIMdM1sGQ9rWf6zISUVQI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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