SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd5db08b08be452dd01069825b2ec221b80112081b02c942e20a2eac68bf10a51' 
  AND token = 'Hm1js1Z2MddEnG76CQtDwVHsgY0NzHP5i4UX6BrGxio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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