SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '11c15c4910f9d83c834febd4b81fc525b3c4ebc51885fe89d634ca21815e38c1' 
  AND token = '71plwhouz6tFfvR9Ozx4LBGrSy+u32bpchaDH0zJEDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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