SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '160125c9d83b3ab4002ce800dfe5525af8efe0fd4579cfa9bcd3b9efab402da6' 
  AND token = 'p9EN2sc9zSJcvJ/iwuAMqJ/0vgJtzvkPMjWNe+0nQAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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