SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edb346c59b4aff83882b979d9bbe1359256ec868a21d45afb94a26b6576f4d7f' 
  AND token = 'twhf6tlbz81nnyvOchCPyMhLQe+mM5ucoUsuxLuyG7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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