SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6a638d24dd884f353f0e8f0345316dfd3d3d674233ec793e483b8529d66a8bd0' 
  AND token = 'rqT6WiEaPtFFAGt3ntzhOeDGUa2fUo9MJ6N1IBZnpPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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