SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b61f578749e922781fdf28b3663058a2f8d69ad022dbdc5e1966cb3df85a429' 
  AND token = 'Bn0dtxHrRwvmX8S/Mmhgs7ckUBXKPUDR7juggw+UC3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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