SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f1929cf3fcf98fb392e6086532771e8d5b9545e0548e4bc0d7898c207676e49' 
  AND token = 'PUfBYihYNuQH/MN9+L4KBogFmjqjZEYwLJQteepC9co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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