SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3be604d5288cf671e32e9842cfe090301f210ef155905d41ee6daf7d8291d3d2' 
  AND token = 'YCxGOz4zjifsB5YFDzzCtR28u0M/uR7cTensLUFPMpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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