SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deffe2753a5ae9c65e17eabf9344419c13cda64012854c9d3341e29659d2539c' 
  AND token = 'xsPGuiZNjlyiEL47QamYXnmjMGLOw+/CSfXn0kdWtlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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