SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5c865f9849b0d392ec6412216648fddcf9fc75a1e09e263d1a2f615b00fca851' 
  AND token = 'eEhFSg7HZdxgi+wlXKJAJOgJ3Lv8Dmiu12b6kACo0TA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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