SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b24dc3110a797e9e276c3f837222d2d85dc563d3b1184d49936e368cc803c7fe' 
  AND token = 'dj8fGB/oDiKrsbktSflSIzCHNsj+vmEe18ujwzG4+lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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