SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3a6c9795fff63fb46917cc61a57447e14eca08b8b8054b006a89c9c9ce8135d3' 
  AND token = 'z3JmnXeaM/GkpSiw4TpyKy/BzL0R8dIlMt2/DRIbLO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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