SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b728ac71c4ecd8656712c3865447906d2e6a47681885937f8e0b918769588663' 
  AND token = 'O9BhWW59Dqf+dxJ0xViC90Ah8hlnSfSHyJz6Yslcjjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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