SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'df9b3f3bf705621300815070a075ab60500965c67b8c84cf7a60d1873e433a65' 
  AND token = 'fhSbo3bVYKNdzZ5u9vds5VHjQ+vdt73HiglYGjLyNsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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